1. Field of the Invention
The present invention relates to a mounting device for fastening a module onto a component. In particular, the present invention relates to a mounting device for fastening a module onto an outside housing of another component, as well as relating to a fastening screw for the mounting device.
2. Description of the Related Art
The related art involves electronic units, serving as modules, which can be mounted by means of fastening screws on a component, for example, on an outside housing of another module.
FIG. 3 illustrates such a situation according to which a module 1 as an electronic analyzer of a filling level meter is to be attached as an additional module by means of a screw connection to an outside housing 2 of the filling to level meter. For mounting, the module 1 is attached to a supporting element (not shown in FIG. 2) of the outside housing 2 before being fastened [onto the component] so that the module 1 is supported thereon.
According to FIG. 3, the outside housing 2 has a fastening dome 3 as a thread carrier with a blind thread 4 for receiving a thread arranged on a shaft 5 of a fastening screw 6. For this purpose the fastening screw 6 is guided through a through-opening 7 arranged on a screw carrier 8 and is screwed into the thread of the fastening dome 3. Because of tolerances in dimensions of the parts involved in the fastening, in particular the supporting element with regard to its dimensions and its position, the screw carrier 8 does not lie directly on the end face of the fastening dome 3 but instead is pulled into surface contact with the fastening dome 3 only by being tightened “until it locks” by means of the fastening screw 6 is the screw carrier 8 drawn into surface contact through the screw head 6 resting on the screw carrier 8, i.e., it is pressed against the end face of the fastening dome 3 without any gaps so that mechanical stresses build up in the parts involved.
What is not appreciated by the prior art is that the disadvantage of such a fastening device consists of the fact that the mechanical stresses built up due to the lack of compensation for tolerance can lead to excessive loads to failure of the screw carrier 8 due to cracking or breakage when the dimensional tolerances of the parts involved add up unfavorably. Furthermore, such a static long-term load can cause a settling behavior due to the increase in material deformation over a period of time when using plastic for the parts involved so that the pre-stress is reduced; but, in the worst case, it disappears completely.
Accordingly, there is a need for an improved mounting device with which the tolerances of the parts involved will be compensated for.